Autosomal recessive non-syndromic hydrocephalus [OMIM#236600] is characterized by onset in utero of enlarged ventricles due to a disturbance of cerebrospinal fluid accumulation. In general, the causes of hydrocephalus are heterogeneous and the majority of cases are secondary to neural tube defects, intracranial hemorrhages, trauma, tumors, teratogens or brain malformations. The remaining cases can be divided into the syndromic (two thirds of cases) and non-syndromic (one third of cases).